Each one of Arduino Pins can be used to power devices that use up to 20 mA, this is a very small amount of current to drive, just enough to run an LED. If you try working to drive something like bigger current the Arduino pin will immediately stop functioning, and could potentially burn out the whole processor. To drive bigger loads like Incandescent lamps, motors and other high current electrical equipment you need to use an external component the can switch ON or OFF and driven by Arduino Board pin. One such device is called a MOSFET(Metal Oxide Semiconductor Field-Effect) transistor by applying a voltage to one of its pins it is called a GATE. Arduino board will send a voltage to the gate of the MOSFET. MOSFET is a special type of transistor that operates base on the field-effect principle. This means that the electrical will flow though apiece of semiconductor material between the drain and the source pins, when voltage is applied to the Gate Pin the gate will insulate from the rest through a layer of metal-oxide, and there is no current flow from the Arduino Board into the MOSFET. MOSFET allow you to drive devices whose power supply differs from the one used by Arduino Board. As the MOSFET is connected to pin 8, you can also used the analogWrite() function to control the speed of the motor trough PWM(Pulse with Modulation). Below are the demonstration how to use MOSFET to your Arduino Board.
Electronic Parts Required
- Arduino UNO/MEGA/PRO
- IRF520 MOSFET
- 1N4007 Diode
Download the IRF520 MOSFET Datasheet Here | PDF